By Zeeshan Ajmal and Dr. Muhammad Usman
WATER IS a basic need for survival of all living things and key component in determining the quality of our lives. Apart from drinking it to survive, water is also essential for the healthy growth of farm crops and farm stock and is used in the manufacture of many products. It is one of the most important gifts of nature to mankind. But unfortunately, due to indefensible water utilization practices, negligent discarding of industrial effluent, urbanization and rapid population expansion have to be found massive strain on the quality as well as the quantity of water in Pakistan.
There are several problems concerning water, among them major problem is water pollution. The contamination of water resources with various pollutants is the subject of increasing concern these days. Polluted wastewater is being used for agricultural purposes and thus, is being added into our food chain. Scarcity of water in terms of quality and quantity has resulted in increased waterborne diseases and other health problems. In Pakistan, 72 million people out of a population of over 180 million are deprived of having access to safe drinking water. Pakistans water quality ranks 80th out of 122 nations because of its poor management and monitoring (UNESCO, 2000).
The most concerning problems with water in Pakistan which are produced through different types of industries like agriculture, leather, textile, oil refinery and pharmaceuticals. Heavy metals, azo-dyes and pesticides are the widely reported pollutants in Pakistan. Azo dyes-contaminated effluents from textile industries have proved as a serious issue because of their negative impact on water ecosystems and human. Due to polluted water, very serious health issues are arising. The effects of the pollutants may not be quite evident immediately but with the passage of time their imperceptible effects are of fatal in nature. Apart from these well known pollutants, serious threats to water quality are being posed by emerging pollutants including hydrocarbons, polychlorinated biphenyls (PCBs), nitro-aromatic compounds and pharmaceutical compounds and personal care products.
Hydrocarbons:
Hydrocarbons are organic compounds of hydrogen and carbon including mainly polycyclic aromatic hydrocarbons (PAHs) and aliphatic or petroleum hydrocarbons. Incomplete combustion or pyrolysis of organic substances such as wood, carbon or mineral oil produces PAHs. These have very damaging effect on aquatic life. Such combustion processes include food preparation in households and food shops; discharge of storm runoff with PAHs from car exhaust particles and road runoff, discharge of certain petroleum products from garages, vehicle washing and maintenance, fuel stations and also from incomplete combustion processes in urban landfills. Frequently anthropogenic PAHs come in water from house fires, heat and energy power stations, vehicle traffic, waste incineration and industrial plants. PAHs concentrate in sewage sludge due to their low biodegradability and they are considered as priority pollutants any community due to their toxicology, persistence and carcinogenic effects.
In terrestrial environment all forms of plants and animals are susceptible to oil spill contamination but main source of hydrocarbon pollution is the oil leakage from offshore facilities, pipelines and petroleum storage tanks. In Pakistan major pollution participants are petroleum refining industries in Multan, Karachi and Rawalpindi.
Polychlorinated biphenyls
Polychlorinated biphenyls (PCBs) are also devastating pollutants. They are used as hydraulic liquids, hydraulic oils, emollients for synthetic materials, lubricants, impregnating agents for wood and paper, flame protective substances, carrier substances for insecticides and in transformers and condensers. PCBs have become an immediate threat to public health, water, agriculture, and the local as well as global environment because of poor management and the low level of awareness among stakeholders and government. The initial surveys indicate that up to 80 per cent of the samples contain PCBs, equaling to thousands of tons of PCB contaminated oils and equipment in the power transmission network in Pakistan. PCBs are not produced in Pakistan. However, at present we do not have adequate technology to destroy the PCBs. According to Stockholm Convention (to whom Pakistan is a party), equipments containing PCBs should be phased out in 2025 which is expected to increase the extent of PCB pollution.
Nitro-aromatic compounds
Anthropogenic activities are root cause of nitro-aromatic compounds, relatively rare in nature. The 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (picric acid) are the prominent members of this group. Due to the explosive properties of nitro-aromatic compounds, these compounds are widely used for military and industrial purposes to synthesize many diverse products, including dyes, polymers and pesticides. TNT has historically been the most widely used military high explosive. Extensive use of nitro-aromatic compounds has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group and stability of the benzene ring, makes nitro-aromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity and easy reduction into carcinogenic aromatic amines.
Pharmaceutical compounds and personal care products
Pharmaceutical pollution has been given little attention. Pharmaceutical residues are emerging environmental pollutants with great health concern. Various research studies in diverse international locations agree that pharmaceuticals are widely found in local aqueous environments. Waste streams and effluents from hospitals and pharmaceutical industry, wastewater treatment plants and livestock have been identified as major contributors of pharmaceutical pollution. There are about 400 pharmaceutical manufacturing companies including those operated by 25 multinationals present in Pakistan. Each company produces an average of 100 products and millions of units are produced. In addition to that, Pakistan has a number of domestic pharmaceutical manufacturers, making generic versions of drugs. Large quantities of commercial pharmaceuticals are now being used for medical and agricultural purposes. The wastewater discharged from pharmaceutical industries is small in volume; but it is highly polluted, because of presence of substantial amounts of organic pollutants.The pharmaceutical industry showed deep concern for the disposal of wastewater generated in the factory without being treatment. It is important for the industry to develop its own wastewater treatment system before discharging the effluent in order to meet the National Environmental Quality Standards (NEQS). As polluted wastewater is being discharged into local water bodies, the pharmaceutical residues present in wastewater are becoming part of food chain resulting in serious health hazards.
Water pollution is ubiquitous in Pakistan. People are concerned about the quality of water they drink. Therefore, a detailed study at national level is required to locate the presence of these pollutants and determine extent of environmental pollution. Moreover, cost-effective and environmental friendly ways to treat wastewater should be designed. Environment related legislations should be implemented by Government Agencies especially for industrial emissions and their management.
The writers are associated with the Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad. They can be reached at <muhammad.usman@uaf.edu.pk> and <musmanch@yahoo.com>